Wire spool package

ABSTRACT

A protective package for a spool of wire, said package comprising a cuplike container having a longitudinal opening in the periphery thereof and including a center post having an external portion which fixedly supports the container and an internal portion which rotatably supports a spool of wire, and a cylindrical cap which slidingly engages the circular rim of the container thereby retaining the spool wire within said container.

o mted States Patent [151 3,635,333 Bonis et al. 1 Jan. 18, 1972 54] WIRE SPOOL PACKAGE 3,350,535 10/1967 Simon ..206/52 w [72] Inventors: Scott R. Bonis, Stow; Thomas E. Salzer, FOREIGN PATENTS 0R APPLICATIONS Bedford; David R. Robiilard, Westboro, ll f M 1,083,268 9/1967 Great Britain ..206/52 W [73] Assignee: Raytheon Company, Lexington, Mass. Primary Examiner wmiam Dixson In [22] Filed: Sept. 19, 1969 Atl0rneyHarold A. Murphy and Joseph D. Pannone A protective package for a spool of wire, said package com- P 'i "206/52 prising a cuplike container having a longitudinal opening in 2 'l i 2 w the periphery thereof and including a center post having an I 1 0 external portion which fixedly supports the container and an internal portion which rotatabiy supports a spool of wire, and a cylindrical cap which siidingly engages the circular rim of [56] References Cited the container thereby retaining the spool wire within said con- UNITED STATES PATENTS 573,563 12/1896 Yeakel ..206/52 W 4 Claims, 9 Drawing Figures WIRE SPOOL PACKAGE BACKGROUND OF THE INVENTION This invention relates generally to protective packages for wire spools and is concerned more particularly with a protective package for a spool of fine wire which package also serves as a dispenser for the wire on the spool.

Ultrasonic bonding is a process for joining two metallic members without generating high temperatures in the interfacing r'nate rials. In the ultrasonic bonding process, one member is pressed againsta surface of the other member by a bonding tool which is vibrated at high frequency. The resulting scrubbingaction of the first member against the second member causes localplastic deformation in the interfacing materials which forms a metallurgical bond. Since this technique does not require melting of the interfacing materials, ultrasonic bonding is a preferred process, in the semiconductor industry, for attaching fine wire leads, such as 1 mil diameter wire, for example, to metallic pads on the surfaces of semiconductor material. I

Because the energy required for ultrasonically bonding fine wire is low and critical, precautions must be taken to insure reproducibility in the bonding process. Consequently factors which affect power delivered to the bonding interface, such as contamination or projections on the surface of the wire, for examples, must be minimized. For this reason, it is important that the wire be maintainedas clean and smooth as possible prior to the bonding operation.

Generally, the wire, as received from the manufacturer, is wound on a spool which is enclosed in a protective package. However, when the spool is removed from the package for installation on a ultrasonic bonding machine, the fingers of the operator or instruments used by the operator, such as tweezers, for example, may come into contact with the exposed layer of wound wire. As a result, the surface of the wire may become contaminated with fingerprints, oils or other foreign matter which will result in intermittent bonds of poor quality being formed by the ultrasonic bonding machine. Furthermore, when the spool of wire is installed on the ultrasonic bonding machine, it usually is rotatably mounted in an exposed position, such as on a projecting shaft or bar, for example. In this unprotected condition, the wire on the spool may be nicked or scratched by contacts with sharp objects, such as tweezers or fingernails, for example. Consequently, the weakened wire will form defective joints or break when the wire is being extended between two terminal members.

SUMMARY OF THE INVENTION Accordingly, this invention provides a package for spools of wire which package protects the wire not only during transportation and storage but also while the wire is being unwound from the spool for use, such as in an ultrasonic bonding operation, for example. This inventive package comprises a hollow, cylindrical housing having a longitudinal slot in the periphery thereof and an inwardly extending radial flange, at one end, which fixedly supports a hollow, center post within said housing. A spool of wire is rotatably mounted on the center post and retained within the housing by an annular cap which encircles the center post, adjacent the open end of the housing, and slidingly engages the inner surface of the housing. As the wire pays off the spool, it emerges from the housing through the longitudinal slot in the periphery of the housing. Since the wire is helically wound on the shank of the spool, it moves laterally along the slot as it emerges longitudinally therefrom. Consequently, the slot should be longer than the shank of the spool and radially aligned therewith in order to avoid having the wire rub against the ends of the slot. The width of the slot is determined by the necessity of preventing the wire from rubbing against the longitudinal edges of the slot. Since fine wire will curl when rubbed along one side thereof, it will not feed properly through guide devices and holes, such as on the tip of an ultrasonic bonding tool, for example.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, reference is made to the drawings wherein:

FIG. 1 is a side elevational view of the protective package of this invention;

FIG. 2 is a plan view of the open end of the protective package shown in FIG. 1;

FIG. 3 is a plan view of the closed end of the protective package shown in FIG. 1; i

FIG. 4 is an axial sectional view of the protective package shown in FIG. 1 with spool and cover installed;

FIG. 5 is a pictorial view of the package shown in FIG. 4 installed on a typical ultrasonic bonding machine;

FIG. 6 is an enlarged fragmentary view, in axial section of the bonding tool tip shown in FIG. 5;

FIG. 7 is an enlarged, exploded, pictorial view showing how I the protective package of this invention is installed on the machine shown in FIG. 5;

FIG. 8 is an enlarged, diagrammatic view of the bonding tool shown in FIG. 5 bonding a wire lead; and

FIG. 9 is an isometric view of the protective package of this invention with another supporting means.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to the. drawings wherein like characters of reference designated like parts throughout the several views, there is shown in FIGS. 1, 2 and 3 a hollow, cylindrical housing 12 comprising a cylindrical wall 14 disposed in spaced, concentric relationship with a hollow, shaft 16 and integrally connected thereto, at one end of housing 12, by a radially extending wall 18 of housing 12. Cylindrical wall 14 and shaft 16 form respective sidewalls of an annular cavity 20 which terminates, at the closed end of the housing 12, in radial wall 18 and is open at the opposite end of housing 12. Cylindrical wall 14 is provided with a longitudinal slot 22 having an open end adjacent the open end of cavity 20. Shaft 16 is provided with an extended portion which protrudes from the open end of housing 12, beyond the rim of cylindrical wall 14. At the opposite end of housing 12, a pin 26 protrudes from the exterior surface of radial wall 18 and forms an integral part thereof. Alternatively, pin 26 may be made as a separate part and be fixedly attached to radial wall 18, as by journaling for example. The pin 26 is located in the exterior surface of radial wall 18 a predetermined angular distance from the slot 22. The closed end of cavity 20 is provided with an annular shoulder 28 which may be formed integrally with the junction of shaft 16 and radial wall 18 or may be made as a separate ringlike member which slidingly engages shaft 16 and seats against the interior surface of radial wall 18. The entire housing 12, preferably, is made of smooth, transparent, plastic material, such as molded polycarbonate, for example, and, preferably, is molded as an integral unit. Alternatively, cylindrical wall 14, shaft 16 and radial wall 18 may be made as separate pieces and then fixedly attached to one another, as by bonding with, epoxy cement, for example.

As shown in FIG. 4, a spool 30 having a shank portion 32 on which a wire 34 may be helically wound is inserted into the annular cavity 20 of housing 12 by passing shaft 16 through a closely fitting bore 36 in spool 28. Shaft 16 rotatably supports spool 30 within the housing 12 and shoulder 28 provides a bearing surface for the seated end of the spool. When spool 30 is inserted into cavity 20 of housing 12, a loose end of wire 34 is passed through the open end of slot 22 and moves laterally along the slot 22 to the closed end thereof. When not in use, the loose end of wire 34 may be secured temporarily to the exterior surface of cylindrical wall 14 by any convenient means, such as adhesive tape, for example. After spool 30 is assembled into housing 12, it is retained therein by an annular cap 40 which encircles the extended portion of shaft 16 and slidingly engages the interior surface of wall 14, adjacent the open end of housing 12. Cap 40 comprises a cylindrical body having an outwardly extending radial flange 42 which is asymmetrically located between the ends of the body. Thus, the cylindrical end portion 44 of cap 40, on one side of flange 42, is longer than the end portion 44, on the opposite side of flange 42. When the longer end portion 44 of cap 40 is inserted into housing 12, the end surface of portion 44 bears against the adjacent end of spool 30 before the flange 42 of cap 40 can seat against the circular rim of housing 12. In this manner, spool 30 is held nonrotatably on shaft 16 within the housing 12 during transportation and storage. When the wire 34 is to be drawn from spool 30, the cap 40 is removed, reversed and end portion 46 is inserted in housing 12. In this case, the flange 42 of cap 40 seats against the circular rim of housing 12 before the shorter end portion 46 of cap 40 can bear against the adjacent end portion of spool 30. Thus, spool 28 is free to rotate and pay out wire 32 through the slot 22 of housing 12.

As the wire 34 unwinds from the shank portion 32 of spool 30, it passes longitudinally through the slot 22. However, since the wire 34 is wound helically on the shank portion 32 of spool 30, it also moves laterally along the slot 22 as it emerges longitudinally therefrom. Therefore, the slot 22 is required to be longer than the shank portion 32 of spool 30 in order to prevent the wire from rubbing against the ends of the slot 22. The length of slot 22 should also allow for any longitudinal play of the spool on the shaft 16, since the end portion 46 of cap 40 does not bear against the adjacent end portion of spool 30. The surface of shaft 16 is required to be very smooth to minimize friction between the surface of shaft 16 and the perimeter of bore 36 in spool 30. Any friction between the spool 30 and the adjacent bearing surfaces of housing 12 produces a drag on the wire 34 as it emerges from the slot 22. Furthermore, all edges of the slot 22 are rounded and polished to a smooth finish to prevent damaging small diameter wire should it come into contact with the perimeter of slot 22. The housing, preferably, is made of transparent material so that the wire may be inspected for gross defects, such as corrosion, for example, without the spool 30 being removed from the housing 12. Thus, the housing 12 provides an enclosure for spool 30 which protects the wire 34 wound on spool 30 during transportation, storage and use.

FIG. illustrates how the packaged spool shown in FIG. 4 is adapted for use with an ultrasonic bonding machine 50 having a bonding head 52. The bonding head .52 comprises a projecting ultrasonic born 54 and a vertical sideplate 56 which are pivotally supported on pivot bearings 58. Pivot bearings 58 are horizontally mounted in a support member 59 which moves the bonding head relative to an anvil 60. A bonding tool 62 is secured in the distal end ofhom 54, by suitable means, such as by locking screw 63, for example; and is disposed in perpendicular relationship with the work surface of anvil 60. Springloaded clamping jaws 64 are supported in close spaced relationship with the bonding tool 62. As shown in FIG. 7, the packaged spool shown in FIG. 4 may be mounted on the sideplate 56 by sliding the hollow shaft 16 on a mandrel 66 which projects from the sideplate. When the pin 26 which protrudes from the closed end of housing 12 is fully inserted into a suitably located hole 68 in the sideplate 56, the radial wall 18 of housing 12 butts against the adjacent surface of sideplate 56 and the slot 22 in housing 12 is oriented at the proper angle for feeding wire to the distal end of bonding tool 62, as shown in FIG. 5. The loose end of wire 34, temporarily secured to the exterior surface of housing 12, is grasped with tweezers and fed through a hole 70 in ultrasonic horn 54, the hole 70 being in colinear alignment with the slot 22 and the distal end of bonding tool 62. The clamping jaws are held open and the wire 34 passed therebetween. With the jaws still held open, the wire 34, as shown more clearly in FIG. 6, is passed through a tapered hole 72 in the rear of bonding tool 62 and under the working tip 74 of the bonding tool. When the wire 34 is positioned under the working tip 74 so that the loose end of the wire 34 just protrudes from under the toe 76 of the working tip, the clamping jaws 64 are closed on an intervening portion of the wire 34. The toe 76 of the working tip 74 is provided with a rounded comer and the heel 78 of the working tip is provided with a very sharp corner.

FIG. 8 shows a metallic pad 80 on a semiconductor wafer 82 being connected electrically to a terminal post 84 in a supporting base member 86 by means of a fine wire lead 88, such as one-thousandth of an inch diameter aluminum wire, for example. When preparing to ultrasonically bond wire lead 88 in place, the base member 86 is clamped or otherwise held in position on the working surface of the anvil 60 and the bonding tool is positioned over the metallic pad 80. When the bonding operation is initiated, the bonding head 52 is pivoted counterclockwise, as viewed in FIG. 5, a small angular distance such as 4, for example, and is lowered onto the metallic pad 80. Thus, the toe 76 of the working tip presses the underlying wire 32 against the metallic pad 80 and forms the first ultrasonic bond. Upon completion of the first bond, the clamping jaws 64 open and the bonding head moves along the longitudinal axis of wire 32 toward the terminal post 84. SInce the end of the wire is attached to metallic pad 80, during this movement of the bonding head 52, the wire 32 is drawn from the spool 30 and through the slot 22 in housing 12. Any rubbing of the fine wire against the longitudinal edges of slot 22 puts a curl in the wire which may foul the wire as it feeds through the hole 70 in transducer horn 54 or hole 72 in the bonding tool 62. Therefore, it is important that the slot 22 be located tangentially with the wire feeding off the spool and in colinear alignment with the holes 70 and 72 respectively. Consequently, the pin 26 is located at the proper angular distance from the slot 22 to orient the slot into colinear alignment with the respective holes 70 and 72. It is also important, as shown in FIG. 5, that the slot 22 be wide enough to allow the wire 32 to feed tangentially off the spool 30 and pass through the slot 22 without touching the sides thereof. When the bonding tool 62 is positioned over the terminal post 86, clamping jaws are closed and the bonding head 52 is lowered thereby forming a service loop in the wire between the metallic pad 80 and the terminal post 84. For the second bond, the bonding head 52 is not pivoted; and, consequently, the heel 78 of working tip 74 is pressed firmly against the wire during the second bonding operation. As a result, the sharp comer of heel 78 places a nick in the small diameter wire. Upon completion of the second bond, the closed clamping jaws 64 pivot away from the working tip 74 of bonding tool 62 and break the wire at the nicked portion. The bonding head 52 is then raised, and the closed clamping jaws, in pivoting back to the rest position, feed more wire through the hole 72 in bonding tool 62. Thus, the interconnecting lead 86 is formed attached to metallic pad 80, at one end thereof, and to terminal post 84, at the other end thereof, by ultrasonic bonding machine 50.

In FIG. 9, there is shown a modification of the supporting and locking features of the housing 12. The hollow shaft 16 may be replaced by a solid shaft 90 having the cross section of a truncated pyramid and protruding outwardly from the exterior surface of radial wall 18. This modified housing may be mounted on a sideplate, such as 56, for example, by sliding the shaft 90 into a conforming cavity (not shown) in the sideplate 56. The shaft 90 then would support housing 12 nonrotatably on the sideplate 56 and would orient the slot 22 into proper alignment without requiring an auxiliary locating pin, such as 26, for example. Alternatively, the shaft 90 may have other cross-sectional configurations such as a square or an ellipse, for examples. Also, the longitudinal bore in shaft 16, shown in FIGS. 2 and 3, need not have a circular cross section but may have other cross-sectional configurations such as square, elliptical or the truncated triangular shape shown in FIG. 9, for examples.

Thus, there has been disclosed herein a protective package for a spool of wire which protects the wire during transportation, storage and use. K

From the foregoing, it will be apparent that all of the objectives of this invention have been achieved by the structures shown and described. It will be also apparent, howeverfthat various changes may be made by those skilled in the art without departing from the spirit of the invention as expressed in the appended claims. It is to be understood, therefore, that all matter shown and described is to be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A protective package for a spool of wire, said package comprising:

a hollow housing having a closed end, an opposing open and a longitudinal opening in the periphery thereof; first means for rotatably supporting a spool of wire in said housing; and

second means disposed on said housing in predetermined angular relationship with said opening for locating the opening in a preselected position.

2. A protective package for a spool of wire as set forth in claim 1 wherein said first means comprises a shaft having one end fixedly attached to said closed end of the housing and an opposite end disposed adjacent said open end of the housing.

3. A protective package for a spool of wire comprising, in

end

combination,

a hollow housing having a closed end, an opposing open end and a longitudinal opening in the periphery thereof;

a shaft having one end attached to said closed end of the housing, an opposite end disposed adjacent said open end of the housing and an intermediate portion disposed in spaced relationship with said longitudinal opening,

a spool of wire rotatably mounted on said intermediate portion of the shaft;

first means for retaining said spool of wire in said housing;

and

second means disposed on said housing in predetermined angular relationship with said opening for locating the opening in a preselected position.

4. A protective package for a spool of wire as set forth in claim 3 wherein said means comprises a cap having opposed inner and outer surfaces disposed in said open end of the housing; said cap having an outwardly extending annular flange disposed asymmetrically between opposing ends thereof. 

1. A protective package for a spool of wire, said package comprising: a hollow housing having a closed end, an opposing open end and a longitudinal opening in the periphery thereof; first means for rotatably supporting a spool of wire in said housing; and second means disposed on said housing in predetermined angular relationship with said opening for locating the opening in a preselected position.
 2. A protective package for a spool of wire as set forth in claim 1 wherein said first means comprises a shaft having one end fixedly attached to said closed end of the housing and an opposite end disposed adjacent said open end of the housing.
 3. A protective package for a spool of wire comprising, in combination, a hollow housing having a closed end, an opposing open end and a longitudinal opening in the periphery thereof; a shaft having one end attached to said closed end of the housing, an opposite end disposed adjacent said open end of the housing and an intermediate portion disposed in spaced relationship with said longitudinal opening, a spool of wire rotatably mounted on said intermediate portion of the shaft; first means for retaining said spool of wire in said housing; and second means disposed on said housing in predetermined angular relationship with said opening for locating the opening in a preselected position.
 4. A protective package for a spool of wire as set forth in claim 3 wherein said means comprises a cap having opposed inner and outer surfaces disposed in said open end of the housing; said cap having an outwardly extending annular flange disposed asymmetrically between opposing ends thereof. 